Pumping unit with spring connected pitman



Feb. 18, 1969 w. E. JONES I 3,427,887

PUMPING UNIT WITH SPRING CONNECTED PITMAN Filed June 5. 1966 FIG-2. WILL/AM ww A T TORNE Y United States Patent 3,427,887 PUMPING UNIT WITH SPRING CONNECTED PITMAN William E. Jones, 3951 Shannon Drive, Fort Worth, Tex. 76116 Filed June 3, 1966, Ser. No. 555,071 US. CI. 74-41 Int. Cl. F161: 21/38 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to pumping units for oil wells and has reference to springs for dampening shock pulses in sucker rod strings.

Heretofore, helical compression springs were installed directly above the well by mounting the springs between upper and lower plates. The lower plate was connected with the bridle cable of the pumping unit and the upper plate was connected with the polished rod which supports the rod string. The present invention is directed to the installation of a leaf spring between the pitman or pitmans and the walking beam of a pumping unit and whereby the frictional action of the leaves tends to reduce rebound. Also, by mounting the spring at the pitman end of the walking beam, the inertia of the beam lends to the dampening action on the sucker rods.

The primary object of the invention is to provide improved means for dampening shock pulses in sucker rod strin s.

A other object is to reduce the cost of operating a pumping well by reducing shutdown time for repairs.

A further object is to reduce breakage and parting of rods in a pumping well.

These and other objects of the invention will become apparent from the following description and the accompanying drawing, in which:

FIGURE 1 is a side elevational view of pumping unit including a preferred form of the invention.

FIGURE 2 is an enlarged end elevational view of the pumping unit illustrated in FIGURE 1.

FIGURE 3 is a broken perspective view of an end of a walking beam and a pitman and showing an alternate means of mounting the spring, and

FIGURE 4 is a broken side elevational view of a modified form of the invention.

Referring now to FIGURES 1 and 2, the pumping unit shown includes a base frame on a concrete foundation 11, a samson frame 12 and a saddle bearing 13 on top of the samson frame. The saddle bearing 13 pivotally supports a walking beam 14 which has a mulehead 15 on its forward end. A bridle cable 16 on the mulehead 15 is connected with the upper end of a polished rod 17, all in the usual manner. The speed reducer 18, motor 19, cranks 20, counterweights 21 and pitmans 22 are also conventional and are not, therefore, herein described in detail.

The primary feature of the invention as illustrated in FIGURES 1-3 is directed to a semi-elliptical leaf spring 23 which is transversely mounted on the walking beam 14 on the end thereof opposite the mulehead 15. In addition to the spring action to be described, the spring 23 also serves as an equalizer beam for the two pitmans 22. As shown in FIGURES l and 2, the spring 23 is secured to the bottom of the walking beam 14 by U-bolts 24, but in FIGURE 3 the spring is mounted on top of the beam and in which case the position of the U-bolts is reversed.

The upper ends of the pitmans 22 are connected with the extending ends of the springs 23 by hearing blocks 25. Laterally extending wrist pins 26 on the upper ends of the pitmans 22 are journaled in the lower portions of the bearing blocks 25, whereas the upper portions of the blocks are bifurcated to receive the ends of the spring 23. The ends of the spring 23 are rolled to form eyes 27 which receive hinge pins 28 that also extend through the bifurcated portions of the bearing blocks 25.

The form of the invention illustrated in FIGURE 4 has to do with adapting the spring 23 to that type of pumping unit having a single crank and a single pitman 122. Here, the end of the walking beam 114 opposite the mulehead 15 is shorter where it is provided with at least one bracket plate 29 on its side for supporting a bearing assembly 30. The bracket plate 29 extends beyond the end of the walking beam 114 where it is offset to support the bearing assembly 30 at a level whereby the latters axis is approximately level with the top of the beam. A pivoted plate 31, as part of the assembly 30, supports the center of the spring 23 parallel with the length of the walking beam 114. U-bolts 124 are connected with the plate 31 and hold the spring in place. The forward end of the spring 23 is connected with the top of the walking beam 114 by a shackle 32, whereas the remaining end of the spring is pivotally connected with the top of the pitman 122 by a wrist pin 126.

In the operation of either described form of the invention, at the end of each stroke the reversing movement of the rod string is dampened by reason of the action of the leaf spring 23. Because of the location of the spring 23 and its leaf action, rebound is less likely than in the action of coil springs parallel with the length of the sucker rod string.

The invention is not limited to the exemplary constructions herein shown and described, but may be made in various ways within the scope of the appended claims.

What is claimed is:

1. In a well pumping unit including a beam pivotally mounted intermediate its ends for oscillating movement in a vertical plane and including at least one crank driven vertically extending pitman generally beneath said beam, a mulehead on one end of said beam, a leaf spring rigidly mounted at its thickest part on said beam on the end thereof opposite said mulehead and extending therefrom and means pivotally connecting an extending end of said spring with the vertically extending end of said pitman.

'2. In a well pumping unit as defined in claim 1, the construction wherein there are two said pitmans on opposite sides of said beam and parallel with each other, and wherein said leaf spring is transversely mounted on said beam and wherein the extending ends of said spring are pivotally connected with the vertically extending ends of said pitmans.

3. In a well pumping unit as defined in claim 1, the construction wherein there is one said pitman, and where- 4 7/1964 Schaefer I 276-36 8/ 1964 Lott 74--41 FOREIGN PATENTS 6/1924 France. 9/1890 Germany.

FRED C. MATTERN, JR., Primary Examiner.

W. S. RATLIFF, JR., Assistant Examiner. 

